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Oct. 8, 1963 E. J. BARTH ETAL. 25,458

DOUBLE COUNTERSHAFT MULTISPEED TRANSMISSION 8 Sheets-Sheet 1 OriginalFiled Aug. 12, 1958 INVENTORS ELMER J BARTH J. GUSTAFSSON %MALQ W7.

ATTORN EY Oct. 8, 1963 E. J. BARTH ETAL 25,458

DOUBLE COUNTERSHAFT MULTISPEED TRANSMISSION 8 Sheets-Sheet 2 OriginalFiled Aug. 12. 1958 ATTORNEY Oct. 8, 1963 E. J. BARTH ETAL 25,458

DOUBLE COUNTERSHAFT MULTISPEED TRANSMISSION 8 Sheets-Sheet 3 OriginalFiled Aug. 12, 1958 INVENTORSr ELMER J. BAR H CARL J. GUSTAFSSON BY FIG.3

ZLWZ aaz a ATTORNEY Oct. 8, 1963 E. J. BARTH ETAL 25,453

DOUBLE COUNTERSHAFT MULTISPEED TRANSMISSION 8 Sheets-Sheet 4 OriginalFiled Aug. 12, 1958 INVENTORS ELMER J. BARTH CARL J. GUSTAFSSON BYATTORNEY 0 T 1w; E 5 mm I1 I l r H on 09 B 3 mm g B 6 B \\m@ mm @b m9 $355.. mm Q9 I I II. I M tl mm I I :lll t 7 7 x g V G M9 Q 1 I 3 HT--- aOct. 8, 1963 E. J. BARTH ETAL 25,458

DOUBLE COUNTERSHAFT MULTISPEED TRANSMISSION 8 Sheets-Sheet 5 OriginalFiled Aug. 12, 1958.

W i H mm Tm oR W \JU m WI M mm wwa v A fW 6 V B Om L w:

ATTORNEY Oct. 8, 1963 E. J. BARTH ETAL 25,458

DOUBLE COUNTER-SHAFT MULTISPEED TRANSMISSION 8 Sheets-Sheet 6 Original.Filed Aug. 12, 1958 ZEPDMZ m9 v/ "mo INVENTORS ELMER J. BARTH CARL J.GUSTAFSSON ATTORNEY Oct. 8, 1963 E. J. BARTH ETAL 25,453

DOUBLE COUNTERS-[AFT MULTISPEED mnsmssmu 8 Sheets-Sheet 7 Original FiledAug. 12, 1958 g INVENTORS ELMER J. BARTH CARL J. GUSTAFSSON ATTORNEYOct. 8, 1963 E. J. BARTH ETAL 25,458

DOUBLE COUNTERSHAFT MULTISPEED TRANSMISSION 8 Sheets-Sheet 8 OriginalFiled Aug. 12, 1958 INVENTORi ELMER J. BART CARL. .J. GUSTAFSSONATTORNEY United States Patent 25 458 DOUBLE COUNTERSHAFT MULTISPEEDTRANSMlSSION Elmer J. Barth, Toledo, Ohio, and Carl J. Gustafsson,liagcrstown, MIL, assignors to Dana Corporation, Toledo, Ohio, acorporation of Virginia Original No. 3,046,807, dated July 31, 1962,Ser. No. 754,637, Aug. 12, 1958. Application for reissue Apr. 3, 1963,Ser. No. 271,046

20 Claims. (Cl. 74-331) Matter enclosed in heavy brackets [1 appears inthe original patent but forms no part of this reissue specification;matter printed in italics indicates the additions made by reissue.

This invention relates generally to change speed gearing and isparticularly directed to automotive transmissions of the doublecountcrshaft, constant mesh gear type, particularly adapted for use inheavy duty vehicles, such as trucks.

A primary object of the invention is to provide a fully synchronizedunit power transmission wherein the difference between the lowest andhighest speed ratios is high and in which a large number of intermediateratios are available for utilizing the engine at its maximum, peakefficiency under all conditions without the use of auxiliarytransmissions or two speed axles. The transmission structure is providedwith an input shaft, an output shaft, a pair of countershafts, aplurality of change speed gears arranged in a novel manner in relationto each other and which are carried on the aforementioned shafts, aplurality of shifting means located between some of the gears toselectively include any of the gears in the power trains, means foroperating the shifting means, some of which are power operated andothers of which are manually operated, further shifting means beingprovided for condition ing the transmission for forward, neutral andreverse operations. The foregoing arrangement provides a structurewherein a minimum number of change speed gears are sufficient forobtaining a large number of speed ratios in an envelope size comparableto the present day five speed transmissions.

A further object is to provide a transmission structure which is simplein construction, efficient in operation, inexpensive to assemble andmanufacture and is of minimum size and weight.

Further objects and advantages will become apparent upon reading thefollowing specification, together with the accompanying drawings whichform a part hereof.

In the drawings:

FIG. 1 is a sectional view taken substantially along line 1-1 of FIG. 3illustrating the transmission gearing embodied in this invention;

IFIG. 2 is a longitudinal view, partially in section, takensubstantially along line 2--2 of FIG. 3 illustrating a portion of theshifting mechanism;

FIG. 3 is a rear elevation view of the transmission assembly showing theshafts in their proper relationship;

FIG. 4 is a view, partially in section, taken substantially along line4-4 of FIG. 3 showing the shift rods;

FIG. 5 is a diagrammatic view, partially in section, illustrating thepower shifting mechanism;

FIG. 6 is a view taken substantially along line 6-6 of FIG. 4 showing amechanism for controlling the power shifting mechanism;

FIG. 7 is a diagrammatic view of the shift pattern; and

FIGS. 8 through 19 are diagrammatic views showing the various geartrains utilized in this embodiment of the invention.

The invention is here shown embodied in a unit power transmission havingtwelve forward and six reverse ratios. A casing, or housing, containswhat is basically a fully synchronized three-speed countershafttransmission in- Reissued Oct. 8, 1963 'ice eluding means to split thethree speeds to produce six speed ratios. A second countershaft isutilized for another range whereby the six speed ratios are multipliedto produce twelve forward and six reverse speed ratios. The selection ofthe speed ratios is accomplished by means of a shift lever for shiftingthe basic three speed transmission, the means for splitting the inputpower to the countershaft of the three speed unit and the diverting ofthe output power through the second countershaft is accomplishedautomatically by power cylinders subsequent to preselection by separatemanual controls carried on the shift lever.

The transmission is a semi-automatic unit with close steps (26% average)between the gear ratios which is necesary to maintain a high engine rpm.for maximum fuel economy and vehicle speed. This compact design allows atwelve speed transmission package to be produced which is comparable inweight and envelope size to the present day five speed transmissions.This twelve speed transmission is slightly wider, shorter and has lessdepth than the aforementioned five speed transmission. This minimumspace requirement is vital to the truck manufacturer in his efforts toobtain the maximum amount of pay load in the minimum amount of space.

While the drawings illustrate a transmission structure embodying theinvention having twelve forward and six reverse ratios, it will beobvious that the invention may be adapted to other applications whereindifferent numbers of forward and reverse ratios are desired.

TRANSMISSION GEARING In FIG. 1 a transmission case \10 having a frontwall 11, intermediate transverse walls 12 and 13, and a rear wall 14,are provided with suitable apertures to support an input shaft 15, apair of countershafts 16 and 17, and an output or mainshaft 18 parallelto and in spaced relation to the input shaft 15. The output shaft 18 andinput shaft 15 are axially aligned. All of these shafts are rotatablysupported in the transmission case 10 except for one end of the outputshaft 18 which is piloted in a bearing 21 as at 19 within the inward endof the input shaft 15.

The input shaft 15 is adapted to be connected to a source of power bymeans of its splined end 20 through a friction clutch (not shown) and issupported by a bearing 22 in the front wall 11 of the case 10. The inputshaft 15 rotatably carries an input gear 23. A clutch gear 24 isrotatably carried on the output shaft 18 adjacent to and rearward of theinput gear 23. These gears may be alternately connected in a drivenrelationship to the input shaft 15 by means of a synchronizing device inthe form of a positive dual clutch assembly designated in its entiretyat 25. The synchronizing device 25 is splined as at 26 to the inputshaft 15, and is consequently rotatable therewith. A sliding shiftcollar 27 having internal teeth 28 is adapted for selective engagementwith a series of teeth 29 provided on a hub 30 forming part of the inputgear 23 or with a series of teeth 31 mounted on a hub 32 forming part ofthe clutch gear 24.

The input gear 23 and the clutch gear 24 are in constant mesh with apair of drive gears 33 and 34 respectively which are splined or keyed tothe countersliaft 16. Thus, it will be seen that when the shift collar27 is moved to its left-hand position as seen in FIG. 1 the internalteeth 28 will engage the teeth 29 of the hub 30 and operatively connectthe input gear 23 to the drive gear 33. Similarly, when the shift collar27 is moved to its right-hand position so that the teeth 28 engage theteeth 31 on the hub 32, the clutch gear 24 will be operatively connectedto the drive gear 34. The synchronizing mechanism 25 per se is ofconventional design. Therefore, no description is considered necessary,

its function being to gradually bring the various rotative parts whichare to be connected together up to the same speed of rotation prior toeffecting a final shift of the collar 27. A shift fork 35, see FIG. 2,is provided for the purpose of effecting the selective movement of theshift collar 27.

The first countershaft 16 is a high speed or high range countershat'tand further, rotatably carries change speed gears 36 and 37. Either ofthese gears may be connected in a driven relationship to the high speedcountershaft 16 by means of a synchronizing device in the form of apositive dual clutch assembly designated in its entirety at 38. Thesynchronozing device 38 is splined as at 39 to the countershaft 16, andis rotatable therewith. A sliding shift collar 40 having internal teeth4i is adapted for selective engagement with a series of teeth 42provided on a hub 43 forming part of the gear 36 or with a series ofteeth 44 mounted on a hub 45 forming part of the gear 37.

The change speed gears 36 and 37 are in constant mesh with gear portions46 and 47 respectively, of a cluster gear 48 which is rotatably carriedon the output shaft 18. Therefore, it will be seen that when the shiftcollar 40 is moved to its left-hand position as seen in FIG. 1, theinternal teeth 41 will engage the teeth 42 of the hub 43 and operativelyconnect the ear 36 to the cluster gear portion 46. Similarly, when theshaft collar 40 is moved to its right-hand position so that the teeth 41engage the teeth 44 on the hub 45, the gear 37 will be operativelyconnected to the cluster gear portion 47. A shift fork 50, see FIG. 3,is provided for effecting the selective movement of the shift collar 40.

A synchronizing device in the form of a single positive clutch assemblydesignated in its entirety at 49 includes a hub 51 Which is splined asat 52 to one end of the cluster gear 48 and includes a shift collar 53mounted on the hub 51 and movable by means of a yoke 54, see FIG. 2,from a disengaged position to a position wherein it is in engagementwith a series of teeth 55 provided on the hub 32 forming part of theclutch gear 24. it will be seen that when the shift collar 53 is movedto its left-hand position as shown in FIG. 1, it will serve tooperatively connect the cluster gear 48 to the clutch gear 24 and thatwhen it is in its right-hand position, the cluster gear 48 will bedisconnected from the clutch gear 24.

The second countershaft 17 is a low speed or low range countershaft andcarries a drive gear 57 drivingly connected, as at 58, thereto. Thedrive gear 57 is in constant mesh with the cluster gear portion 46.Rotatably carried on the low speed countershaft 17 is a change speedgear 59 which may be connected in a driven relationship thereto by meansof a positive sliding clutch gear 60. The sliding clutch gear 60 issplined as at 64 to the countershaft 17 and is consequently rotatabletherewith. The clutch gear 60 is provided with internal teeth 61 forselective engagement with a series of teeth 62 provided on a hub 63forming part of the gear 59 or with a gear portion 65 of a reverse idlergear cluster 66 by means of the gear teeth 56.

The sliding clutch gear 60 is further provided with a neutral positionlocated between its two engaged positions whereby the transmission canbe operated while the vehicle is stationary. It is obvious that when theclutch gear 60 is in its extreme left-hand position as viewed in FIG. 1,the reverse idler gear cluster 66 will be operatively connected to thesliding clutch gear 60, that when the clutch gear 60 is moved to itsmiddle position it is disengaged and when it is moved to its right-handposition the internal teeth 61 Will engage the teeth 62 on the hub 63,the gear 59 will be drivenly connected to the countershaft 17. A shiftfork 67, see FIG. 3, is provided for effecting the selective movement ofthe clutch gear 60.

The output shaft 18 rotatably carries an output gear 68 which is inconstant mesh with the change speed gear 59. Either the output gear 68or the cluster gear 48 may be connected in a driving relationship to theoutput shaft 18 by means of a synchronizing device in the form of apositive dual clutch assembly designated in its entirety at 69. Thesynchronizing device 69 is splined as at 70 to the output shaft 13, andis therefore rotatable therewith. A sliding shift collar 71 havinginternal and external teeth 72 and 73 respectively is adapted forsclective engagement with a series of internal teeth 74 provided on ahub 75 forming part of the cluster gear 48 or with a series of teeth 76mounted on a hub 77 forming part of the output gear 68. It will be seenthat when the shift collar 71 is moved to its left-hand position as seenin FIG. 1 the external teeth 73 will engage the internal teeth 74 of thehub 75 and operativcly connect the cluster gear 43 to the output shaft13. Similarly, when the shift collar 71 is moved to its right-handposition so that the internal teeth 72 engage the teeth 76 on the hub77, the output gear 63 will be o-peratively connected to the outputshaft 18. A shift fork 78, see FIG. 2, is provided for the purpose ofeffecting the sclective movement of the shift collar 71.

Although FIG. 1 is an expanded cross sectional view, all of the gearsare shown in their proper meshing engagement with the exception of thereverse cluster gear 66, which is shown in phantom. Bearing, in mindthat the gear portion 112 of the reverse cluster gear 66 is in constantmesh with the output gear 63, FIG. 1 can be used to trace the twelveforward and six reverse ratios.

SHIFT MECHANISM In general, the shift mechanism consists of twoindependently operated levers, each having a neutral position. One ofthe levers conditions the transmission for forward, neutral and reverseoperation and the other lever is for changing the various gear ratios inthe aforementioned forward, neutral and reverse positions.

Referring now to FIG. 4, an individual selector lever, not shown, may beconnected by a flexible cable or any other suitable means to a shift rod79 on which is mounted the shift fork 67 for the shifting of the slidinggear clutch 60. The neutral position of this lever permits the vehicleto remain stationary while the gear 57 mounted on the countershaft 17 isused to drive a side mounted power take-off. This control furtherpermits the driver to maneuver the vehicle forward or backward withoutchanging the position of the gear shift lever 8ft.

Since this transmission might simply be described as a three speed, handshifted gear set equipped with an input splitter which is power shifted,and an output splitter which is also power shifted, all twelve ratiosmay be obtained with the gear shift lever 80 in only three positions,note the shift diagram 166 in FIG. 7. This easyto-use diagram allows thedriver to obtain the proper gear ratios either in forward or reversequickly and easily for all driving requirements.

The gear shift lever 50 is provided with means at its lower end forselectively engaging shift rods 81 and 82. Suitable means are providedfor locking one or the other of the rods from shifting when either ofthe rods is in a shifted position. This locking means also forms part ofthe connection for controlling the flow of power to the fluid motorsWhich operate the input and output splitter mechanisms, indicated as awhole by the reference numerals 83 and 84, respectively.

The means for operating the input and output splitters 83 and 84respectively, that is the shifting sections 27 and 71 respectivelythereof, are double acting pressure or fluid operated motors comprisingcylinders 85 and 86, mounted on the transmission cover 87, pistons 88and 89 in the cylinders 35 and 86 respectively, and connected to theforks 35 and 73, which in turn are operatively connected to the shiftingsections 27 and 71, a conduit system, indicated a whole by referencenumeral 90, connected to the cylinders 85 and 86, and to a source ofpower 91 and control valve means 92 (see FIG. 6) in said conduit system90, and operated preferably by the shift rods 81 and 82. The valve means92 is operated to open position, that is, the conduit system 90 is opento the power fluid, when one of the shift rods is moved to neutralposition. The valve means 92 is moved to closed position when the shiftrods 81 and 82 are moved into a shifted position. As seen in FIG. 5, thevalve means is further provided with slides 93 and 94 which serve toconnect either end of the cylinders 85 and 86 to the source of power 91.These slides are connected by means of cables 95 and 96 to manuallyoperable means 113 and 114 respectively, located on the gear shift lever80 for preselecting the desired gear ratios.

A series of interlocks are provided between the shift mechanism and thetransmission gearing to insure safe and efficient operation of thetransmission.

As clearly shown in FIG. 4, with the shift lever 80 in its neutralposition, notches 97 and 98 in the shift rods 81 and 82 are aligned.This permits a poppet 99, interlock pin 100 and an interlock rod 101 tomove away from the control valve body 102. The interlock parts 99, 100and 101 are moved out of engaged position by the fluid pressu re actingon the valve 92. When the interlock rod 101 is moved from its engagedposition (see FIGS. 5 and 6), interlock bridge 103 drops down to releasethe shift rods 104 and 105 of the power shifted elements 83 and 84. Thefluid pressure that opened the valve 92 is now free to pass into thepower cylinders 85 and 86. Movement of either shift rail 81 or 82 out ofits neutral position will displace the interlock rod 101 causing theinterlock bridge 103 to engage and lock the shift rods 104 and 105 fromshifting and also cut off the incoming fluid pressure.

Referring briefly to FIG. 7, it will be noted that there are twoseparate shift patterns 106 and 107; namely, one pattern 107 havingforward, neutral and reverse positions and the other pattern 106 havingfour positions for changing the gear ratios including the forward,neutral and reverse positions of pattern 107. The gear ratios of thelast mentioned shift pattern 106 are divided between 21 low and highrange of speed ratios and the splitter 83. The low range includes first,second, third, fourth, fifth and sixth speeds for forward, neutral andreverse operation of the transmission, while the high range includesseventh, eighth, ninth, tenth, eleventh and twelfth speeds for forwardoperation of the transmission only.

Due to the fact that the cluster gear 48 is the focal point for all thepower flowing through the transmission, it will be noted that the inputpower terminates at this cluster gear 48 carried on the mainshaft 18.The output power emanates from the cluster gear 48 and may be divertedinto the countershaft 17 for first through sixth speeds, or coupleddirectly to the mainshaft 18 for seventh through twelfth speeds.

Instead of one drive gear meshing with one countershaft driven gear, asin a conventional transmission, two input drive gears 23 and 24 meshwith two driven gears 33 and 34 respectively, on the countershaft 16.The synchronizer 25 located between the two input drive gears 23 and 24is power shifted and clutches one or the other to the input drive shaft15. A splitter shift is made for every gear change if the transmissionis shifted progressively from first through twelfth speeds. With thisarrangement, two different input ratios may be used with the basicthree-speed hand shifted gear set.

A power shifted synchronizer 69 is located between the cluster gear 48and the gear 68 and clutches one or the other to the mainshaft 18 forfinal output drive. This shift is made only once during a progressiveshift pattern from first through twelfth speed. With this arrangement,two different output ranges may be used in conjunction with the six gearratios obtained from the input splitter 83 and the basic three speed,hand shifted gear set.

The power cylinders and 86 which do the actual shifting of the input andoutput splitters 83 and 84 are double acting. The power fluid isadmitted or exhausted from each end of the cylinders 85 and 86 through acontrol valve 92. The position of the slides 93 and 94 inside this valvedetermines whether the power fluid is admitted or exhausted from thecylinders 85 and 86. The position of the slides 93 and 94 inside thecontrol valve 92 may be selected by the driver when it is necessary ordesirable to effect a change of ratios.

LOW RANGE, FORWARD, NEUTRAL AND REVERSE Referring to FIGS. 1 and 2specifically, the low range speed ratios are effected by actuation ofthe shift fork 78 rearwardly, to the right in FIG. 2, whichsimultaneously shifts the shift collar 71 to the right in FIG. 1 also.Shifting of the shift collar 71 locks the output gear 68 to themainshaft 18. With the shift fork 78 in this position interlock pin 108,see FIG. 3, is disengaged from the shift rail 79, thus allowing theshift rail 79 to be moved to any one of its three positions. Referringnow to FIG. 4, the shift rail 79 is shown so that the clutching gear 60locks the gear 59 to the countershaft 17. If the shift rail 79 is movedto the left in FIG. 4 so that the poppet 109 engages notch 110, theclutching gear 60 will be disengaged from the gear 59 whereby thetransmission is neutralized from the vehicle. This allows a side mountedpower take-off to be operated from the gear 57 at all six speedsavailable in low range. When the shift rail 79 is further moved, to theleft in FIG. 4, so that the poppet 109 engages notch 111, the clutchinggear 60 will mesh with a reverse idler gear 65, thereby conditioning thetransmission for reverse operation.

LOW RANGE-FIRST SPEED The transmission is conditioned for low range,forward operation by locking output gear 68 to the mainshaft l8 and gear59 to the countershaft 17 as previously described. The input splittcrshift fork 35 is shifted rearwardly, to the right in FIGS. 1 and 2,causing the shift collar 27 to clutch the gear 24 to the input shaft 15.The manually actuated shift fork 50 is also shifted rearwardly causingthe shift collar 40 to clutch gear 37 to the countershaft 16.

The power flow in first speed, see FIG. 8, is through the followinggears in the order recited: from the input shaft 15 to the clutch gear24, rotatably carried on the mainshaft 18, to the drive gear 34 keyed tothe countershaft 16, to change speed gear 37 clutched to counter-shaft16 which meshes with gear portion 47 of the cluster gear 48 rotatablycarried on mainshaft 18, to drive gear 57 keyed to countershaft 17, togear 59 clutched to countershaft 17, to gear 68 clutched to mainshaft 18thence out the driven mainshaft 18.

LOW RANGESECOND SPEED Second speed is obtained by shifting the inputsplitter shift fork 35 forwardly, to the left in FIGS. 1 and 2, causingthe shift collar 27 of the synchronizing clutching assembly 25 to clutchthe gear 23 to the input shaft 15, thereby locking the gear 23 to theinput shaft 15.

The power flow for second speed, see FIG. 9, is substantially the sameas first speed except that gear 23 and its meshing gear 33 are used inplace of the clutch gear 24 and the drive gear 34.

LOW RANGE THIRD SPEED For third speed the input splitter shift fork 35is moved rearwardly coupling the input shaft 15 and the clutch gear 24together as previously described for the first speed.

The manually actuated shift fork 50 is shifted forwardly coupling thechange speed gear 36 to the countershaft 16 as previously described.

The power flow for third speed, see FIG. 10, is then through thefollowing gears in the order recited: from the input shaft to the clutchgear 24, to the drive gear 34, to the change speed gear 37, to theforward gear portion 46 of the mainshaft cluster gear 48, to the drivegear 57, to the gear 59, to the mainshaft output gear 68 and out thedriven mainshaft 18.

LOW RANGE-FOURTH SPEED The fourth speed gear ratio is obtained by movingthe input splitter shift fork 35 forward as previously described insecond speed.

The flow of power is then substantially the same as third speed except,see FIG. 11, that the gear 23 and its mating counterpart drive gear 33replaces the clutch gear 24 and the drive gear 34 combination.

LOW RANGE-FIFTH SPEED Fifth speed ratios are obtained by shifting theinput splitter shift fork 35 rearwardly. This causes the input shaft 15to be coupled to the clutch gear 24 as previously described. Themanually actuated shift fork 54 is shifted forwardly to the left inFIGS. 1 and 2, moving the shift collar 53 of the interposedsynchronizing assembly 49 in the same direction. The shift collar 53straddles the clutching teeth 55 of the clutch gear 24 and the mainshaftcluster gear 43 thereby coupling said cluster gear 48 to the clutch gear24. The shift fork 50 is in its neutral position, thereby isolating thecountershaft 16.

The power flow, see FIG. 12, is then from the input shaft 15 to theclutch gear 24, to the forward gear portion 46 of the mainshaft clustergear 48, to the drive gear 57, to the speed gear 59, to the output gear68, and thence out the driven mainshaft 18.

LOW RANGE-SIXTH SPEED The input splitter shift fork 35 is shiftedforwardly, to the right in FIGS. 1 and 2 which simultaneously shifts theshift collar 27 in the same direction causing the gear 23 to becomeclutched to the input shaft 15 as explained before.

Therefore, the flow of power of the sixth speed, see FIG. 13, differsfrom the fifth speed power flow only in the use of the input gear 23,front drive gear 33 combination. and the clutch gear 24, rear drive gear34 combination.

HIGH RANGE-FORWARD The next six ratios are effected by the actuation ofthe shift fork 78 being shifted forwardly, to the left in FIGS. 1 and 2.This causes the shift collar 71 to straddle the clutching teeth 74 onthe internal periphery of the cluster gear 48 and the splined teeth 70of the mainshaft 18 thereby locking the cluster gear 48 to the mainshaft18.

HIGH RANGE-SEVENTH SPEED The input splitter shift fork 35 is shiftedrearwardly, to the left in FIGS. 1 and 2, and simultaneously moves theshift collar 27 in the same direction. The shift collar 27 straddles thespline teeth 26 of the input shaft 15 and the clutching teeth 31 of theclutch gear 24 thereby locking the input shaft 15 to the clutch gear 24as previously described.

The manually actuated shift fork 50 is also moved rearwardly and causesthe shift collar 40 to clutch the change speed gear 37 to thecountershaft 16, as heretofore described.

The power flow for seventh speed is then through the following geartrain, see FIG. 14, in the order recited. from input shaft 15 to theclutch gear 24, to the drive gear 34, to the change speed gear 37, togear portion 47 of the cluster gear unit 48, then out the drivenmainshaft 18.

HIGH RANGEEIGHTH SPEED The high range eighth speed ratio follows apattern similar to the seventh speed ratio, the only difference beingthat the input splitter shift fork 35 is shifted forwardly, therebydisengaging clutch gear 24 from and engaging input gear 23 to the inputshaft 15.

The power flow, see FIG. 15, is then from the input shaft 15, to theinput gear 23, through the front drive gear 33, from which point on theflow of power is the same as that described for seventh speed.

HIGH RANGE-NINTH SPEED For ninth speed the input splitter shift fork 35is shifted rearwardly causing the clutch gear 24 to be locked to theinput shaft 15.

The shift fork S0 is shifted forwardly, thereby joining the change speedgear 36 to the mainshaft 18.

The power flow, see FIG. 16, is then through the input shaft 15, theclutch gear 24, the drive gear 34, the change speed gear 36, the forwardgear portion 46 of the mainshaft cluster gear 48 and. out the drivenmainshaft 18.

HIGH RANGE-TENTH SPEED Tenth speed is practicably the same as ninthspeed except that the input splitter shift fork 35 is shifted forwardlyunlocking the clutch gear 24 and lOcking the input drive gear 23 to theinput shaft 15.

The power flow, see FIG. l7, is then through the input drive gear 23 tothe front drive gear 33 then through the same path as ninth speed.

HIGH RANGE-ELEVENTH SPEED Eleventh speed is the direct drive of thetransmission unit. The input splitter shift fork 35 is moved rearwardlythereby clutching the input shaft 15 to the clutch gear 24. Shift fork54 is moved rearwardly to the right in FIGS. 1 and 2 clutching themainshaft cluster gear 48 to the clutch gear 24.

The power flow, see FIG. 18, is then from the input shaft 15, to theclutch gear 24, through the cluster gear 48 and out the driven mainshaft18.

HIGH RANGE-TWELETH SPEED Twelfth speed is similar to eleventh speedexcept that the input splitter shift fork 35 is moved in a forwardlydirection uncoupling the clutch gear 24 and coupling the input drivegear 23 to the input shaft 15.

The power flow, see FIG. 19, is then from the input drive gear 23, tothe front drive gear 33, to the rear drive gear 34, to the clutch gear24 and out the driven mainshaft 18, as explained above.

A transmission having twelve forward and six reverse speeds is thusprovided by using a freely rotatable cluster gear on the output shaft asthe focal point of the output power in conjunction with a pair ofcountershafts which are parallel to and in a spaced relationship to theoutput shaft. This arrangement reduces the axial length required for atransmission of this speed range, which is vital in the effort ofgetting a maximum amount of pay load in a minimum amount of space in avehicle.

It will be obvious that various changes in the details, which have beenherein described and illustrated in order to explain the nature of thisinvention, may be made by those skilled in the art within the principlesand scope of the invention as expressed in the appended claims.

What is claimed is:

1. In a transmission, the combination of a drive shaft, a driven shaft,a pair of countershafts, means for providing a relatively low speedrange between said drive and driven shafts through both of thecountershafts and including a first synchronizing clutch engageable tocondition the transmission for the low speed range, means for providinga higher speed range between said drive and driven shafts through one ofthe countershafts and including the first synchronizing clutchengageable to condition the transmission for the higher speed range,means for providing a plurality of speed ratios between the drive anddriven shafts having close steps therebetween in either the low or highspeed ranges and including a second synchronizing clutch, means forproviding a direct drive between said drive and driven shafts andincluding the second and a third synchronizing clutch cngageable tocondition the transmission for the direct drive, and means for providinga forward and reverse drive speed range between the said drive anddriven shafts through both of said countershafts and including means forpermitting the reverse driven to be engageable in only the low speedrange and further including a positive clutch engageable to conditionthe transmission for the forward and reverse drive.

2. A chinge speed transmission comprising an input shaft, a high speedcountershaft, a low speed countershaft, an output shaft, driving gearscarried on the input shaft and output shaft, synchronizing clutch meansto selectively connect the driving gears in a driven relationship to theinput shaft, a pair of drive gears drivingly connected to the high speedcountershaft and meshing with the driving gears carried on the input andoutput shafts, a pair of change speed gears carried on the high speedcountershaft, a second synchronizing clutch means to selectively connectthe change speed gears in a driven relationship to the high speedcountershaft, an output gear carried on the low speed countershaft, asecond output gear carried on the output shaft, and meshing with saidoutput gear on the low speed countershaft, a cluster gear carried on theoutput shaft provided with one gear portion meshing with one of saidchange speed gears, another gear portion of said cluster gear meshingwith the other change speed gear, one of said gear portions furthermeshing with a low speed countershaft driving gear, a thirdsynchronizing clutch means to selectively connect the second output gearor the cluster gear to the output shaft, and a positive clutchengageable to connect the first output gear to the low speedcountershaft to condition the transmission for forward drive.

3. A change speed transmission comprising a casing containing a driveshaft, a first countershaft, a second countershaft, and a driven shaft,a driving gear carried on the drive shaft, another driving gear carriedon the driven shaft, clutch means to selectively connect the drivinggears in a driven relationship to the driving shaft, drive gearsdrivingly connected to said 'first countershaft and meshing with thedriving gears carried on the drive and driven shafts, change speedgearing carried on said first countershaft, a cluster gear carried onthe driven shaft having gear portions for meshing with said change speedgearing of said first countershaft, a drive gear drivingly connected tothe said second countershaft and meshing with one of said gear portionsof said cluster gear, an output gear carried on said secondcountershaft, a second output gear carried on the driven shaft andmeshing with said output gear on said second countershaft, and clutchmeans on the first countershaft and said driving and driven shaftsincluding the first mentioned clutch means to selectively include any ofthe change speed gears in the power train.

4. In a change speed transmission, the combination comprising a driveshaft, a driven shaft, a pair of countershafts parallel to said driveand driven shafts and to each other, a pair of driving gears carried onthe drive and driven shafts and adapted to be selectively connected tothe drive shaft, a pair of drive gears drivingly connected to one ofsaid countershafts and meshing with said driving gears on said drive anddriven shafts, change speed gearing carried on said one countershaft andadapted to be selectively connected thereto, a cluster gear carried onthe driven shaft and adapted to be selectively connected thereto, saidcluster gear meshing with said change speed gearing on said onecountershaft, a drive gear drivingly connected to the other countershaftand meshing with said cluster gear, an output gear on said othercountershaft, another output gear on said driven shaft adapted to beselectively connected thereto and clutch means disposed on at leastthree of said shafts to selectively include any of the gearing in thepower train.

5. A change speed transmission comprising a drive shaft, a driven shaft,a first and second countershaft parallel to said drive and driven shaftsand to each other, a first gear group adapted to receive power from saiddrive shaft, a second gear group on said driven shaft and said firstcountershaft and adapted to receive power from said first gear group, athird gear group disposed on said second countershaft and said drivenshaft, and means selectively operative to direct the flow of power fromsaid second gear group through said third gear group, said last namedmeans also being selectively operative to direct the flow of power fromsaid second gear group directly to said driven shaft.

6. A change speed transmission comprising a drive shaft, a driven shaft,a first and second countershaft parallel to said drive and driven shaftsand to each other, a first gear group adapted to receive power from saiddrive shaft, a second gear group on said driven shaft and said firstcotmtershaft, means operative to supply power through said first geargroup to said second gear group, means operative to supply power fromsaid drive shaft directly to said second gear group, a third gear groupdisposed on said second countershaft and said driven shaft, and meansselectively operative to direct the fiow of power from said second geargroup through said third gear group, said last named means also beingselectively operative to direct the flow of power from said second geargroup directly to said driven shaft.

7. A change speed transmission comprising a drive shaft, a driven shaft,a first and second countershaft parallel to said drive and driven shaftsand to each other, a first gear group on said drive shaft, driven shaft,and first countershaft, a second gear group on said driven shaft andsaid first countershaft, clutch means selectively operative to supplypower through said first gear group to said second gear group, clutchmeans selectively operative to supply power from said drive shaft tosaid second gear group, a third gear group disposed on said secondcountershaft and said driven shaft, and clutch means selectivelyoperative to direct the flow of power from said second gear groupthrough said third gear group, said last named clutch means also beingselectively operative to direct the flow of power from said second geargroup directly to said driven shaft.

8. A change speed transmission comprising a drive shaft, a driven shaft,a first and second countershaft parallel to said drive and driven shaftsand to each other, a first gear group adapted to receive power from saiddrive shaft, a second gear group on said first countershaft and saiddriven shaft and including a cluster gear, means operative to supplypower from said first gear group through the second gear group to thecluster gear, means operative to supply power from said drive shaft tosaid cluster gear, a third gear group disposed on said secondcountershaft and said driven shaft, and means selectively operative todirect the flow of power from said cluster gear through said third geargroup, said last named means also being selectively operative to directthe flow of power from said cluster gear directly to said driven shaft.

9. A change speed transmission comprising a drive shaft, a driven shaft,a first and second countershaft parallel to said drive and driven shaftsand to each other, a first gear group on said drive shaft, driven shaft,and first countershaft, a second gear group on said driven shaft andsaid first countershaft, first clutch means on said driving shaftoperative to supply power through selected gears of said first geargroup to said second gear group, second clutch means on the driven shaftoperative to supply power directly from said drive shaft to said secondgear group, a third gear group disposed on said second countershaft andsaid driven shaft, and a third clutch means disposed on said drivenshaft operative to direct the flow of power from said second gear groupthrough said third gear group, and said third clutch means also beingoperative to direct the flow of power from said second gear groupdirectly to said driven shaft.

10. A change speed transmission comprising a drive shaft, a drivenshaft, 21 first and second countershaft parallel to said drive anddriven shafts and to each other, a first gear group adapted to receivepower from said drive shaft, a second gear group on said driven shaftand said first countershaft, means operative to supply power throughsaid first gear group to said second gear group, means operative tosupply power from said drive shaft directly to said second gear group, athird gear group disposed on said second countershaft and said drivenshaft, and means selectively operative to direct the flow of power fromsaid second gear group through said third gear group.

11. A change speed transmission comprising a drive shaft, a drivenshaft, a first and second countershaft parallel to said drive and drivenshafts and to each other, a first gear group on said drive shaft, drivenshaft, and first countershaft, a second gear group on said driven shaftand said first countershaft, clutch means selectively operative tosupply power through said first gear group to said second gear group,clutch means selectively operative to supply power from said drive shaftto said second gear group, a third gear group disposed on said secondcountershaft and said driven shaft, and clutch means selectivelyoperative to direct the flow of power from said second gear groupthrough said third gear group.

12. A change speed transmission comprising a drive shaft, a drivenshaft, a first and second countershaft parallel to said drive and drivenshafts and to each other, a first gear group adapted to receive powerfrom said drive shaft, a second gear group on said first countershaftand said driven shaft and including a cluster gear, means operative tosupply power from said first gear group through the second gear group tothe cluster gear, means operative to supply power from said drive shaftto said cluster gear, a third gear group disposed on said secondcountershaft and said driven shaft, and means selectively operative todirect the flow of power from said cluster gear through said third geargroup.

13. A change speed transmission comprising (1) a drive shaft,

(2) a driven shaft,

(3) a first and second countershaft (a) parallel to said drive anddriven shafts and (b) to each other,

(4) a first gear group adapted to receive power from said drive shaft,

(5) a second gear group including (a) gear means on said firstcountershaft and (b) gear means rotatable relative to said driven shaft(c) and adapted to receive power from said first gear group,

(6) a third gear group (a) disposed on said second countershaft (b) andsaid driven shaft,

(7) and means (a) selectively operative to direct the flow of power fromsaid second gear group through said third gear group,

(b) said last named means also being selectively operative to direct theflow of power from said second gear group directly to said driven shaft.

14. A change speed transmission comprising (1) a drive shaft,

(2) a driven shaft,

(3) a first and second countershaft parallel to said drive and drivenshafts vand to each other,

(4) a first gear group adapted to receive power from said drive shaft,

(5 a second gear group including (a) gear means on said firstcountershaft and (b) gear means rotatable coaxially with said drivenshaft (c) and adapted to receive power front said first gear group,

(6 means operative to supply power through said first gear group to saidsecond gear group,

(7) means operative to supply power from said drive shaft directly tosaid second gear group,

(8) a third gear group disposed on said second countershaft and saiddriven shaft,

(9) and means selectively operative to direct the flow of power fromsaid second gear group through said third gear group.

15. In a transmission, the combination of (l) a drive shaft,

(2) a driven shaft,

(3) a pair of countershafts,

(4) means for providing a relatively low speed range between said driveand driven shafts through both of the counters/lofts (a) and including afirst clutch engageable to condition the transmission for the low speedrange,

(5) means for providing a higher speed range between said drive anddriven shafts through one of the countershafts and (at) including saidfirst clutch engageable to condition the transmission for the higherspeed range,

(6) means for providing a plurality of speed ratios between the driveand driven shafts having close steps therebetween in either the low orhigh speed ranges and (at): including at least a second clutch,

(7) means for providing a direct drive between said drive and drivenshafts (a) and including said first clutch and a third clutch cngageableto condition the transmission for the direct drive.

1 6. A change speed transmission comprising (1) a drive shaft,

(2) a driven shaft,

(3) a first and second countershaft (a) parallel to said drive anddriven shafts and (b) to each other,

(4) a first gear group adapted to receive power from said drive shaft,

(5) a second gear group including (a) gear means on said firstcountershuft and (b) an intermediate means rotatable relative to saiddrive and driven shafts and having gear means drivingly associatedtherewith for engagement with said gear means on the first countershaftand (c) adapted to receive power from said first gear (6) a third geargroup (a) disposed on said second countershaft (b) and said drivenshaft,

(7) and means (a) selectively operative to direct the flow of power fromsaid second gear group through said third gear group,

(b) said last named means also being selectively operative to direct theflow of power from said second gear group directly to said driven shaft.

17. A change speed transmission comprising I an input shaft,

(2) an output shaft,

(3) a high speed countershaft and a low speed countershaft (a) parallelto said input shaft and to said output shaft and to each other,

(4) driving gears associated with said input shaft, clutch meansselectively connecting said driving gears in a driven relationship tosaid input shaft,

(6) a pair of drive gears (a) drivingly connected to the high speedcountershaft and meshing with said driving gears associated with saidinput shaft,

(7) at least a pair of change speed gears carried on the high speedcounter shaft,

(8) intermediate means rotatable coaxially with said input and outputshafts and having gear means associated therewith for engagement withsaid change speed gears on said high speed countershaft,

(9) an output gear carried by said low speed countershaft and beingdriven by said intermediate rotatable means,

() output gear means carried on said low speed counter shaft and saidoutput shaft,

(11) clutch means (a) selectively operative to direct the flow of powerfrom said intermediate rotatable means through said low speedcountershaft,

(b) said last name clutch means also being selectively operative todirect the flow of power from said intermediate rotatable means directlyto said output shaft.

18. A change speed transmission comprising (1) a drive shaft,

(2) a driven shaft,

(3) a flirst and second countershaft parallel to said drive and drivenshafts and to each other and substantially overlapping each other,

(4) first gear means adapted to receive power from said drive shaft fordriving said first counter shaft,

(5) second gear means on said first countershaft,

(6) intermediate means rotatable coaxially with said drive and drivenshafts and being substantially overlapped by said first and secondcountershafts,

(7) third gear means associated with said intermediate rotatable meansfor engagement with said second gear means,

(8) means operative to supply power from said drive shaft directly tosaid intermediate rotatable means (9) fourth gear means on said secondcountershaft and said driven shaft adapted to receive power from saidintermediate rotatable means,

(10) and means selectively operative to direct the flow of power fromsaid intermediate rotatable means directly to said driven shaft.

19. A change speed transmission comprising (1) a drive shaft,

(2) a driven shaft,

(3) a first and second countershaft parallel to said drive and drivenshafts and to each other and sub stantially overlapping each other,

(4) first gear means adapted to receive power from said drive shaft fordriving said first countershaft,

(5) second gear means on said first countershaft including at least apair of gears,

(6) intermediate means rotatable coaxially with said 14 drive and drivenshafts and being substantially overlapped by said first and secondcountershafts,

(. third gear means associated with said intermediate rotatable meansfor engagement with said second gear means,

(8) clutch means selectively operative to direct the flow of power fromsaid drive shaft to said intermediate rotatable means through thedesired gear of said pair of gears of said second gear means,

(9) clutch means operative to supply power from said drive shaftdirectly to said intermediate rotatable means,

(10) fourth gear means including at least a pair of gears on said secondcountershaft and a gear on said driven shaft,

(a) at least one of said gears on said second countershaft being inengagement with said third gear means (b) and another of said gears onsaid second countershaft being in engagement with said gear on saiddriven shaft (c) whereby said driven shaft is adapted to receive powerfrom said intermediate rotatable means (11) and clutch means selectivelyoperative to direct the flow of power from said intermediate rotatablemeans directly to said driven shaft.

20. A change speed transmission comprising (1) a drive shaft,

(2) a driven shaft,

(3) a first and second eountershaft (a) parallel to said drive anddriven shafts and to each other,

(b) and substantially overlapping each other,

(4) a first gear group including at least a pair of gears on said firstcountershaft and adapted to receive power from said drive shaft,

(5) a second gear group adapted to receive power from said first geargroup and including (a) gear means on said first countershaft and (b) anintermediate means rotatable relative to said drive and driven shaftsand being substantially overlapped by said first and second countershaftand having gear means drivingly associated therewith for engagement withsaid gear means on the first countershaft,

(6) a third gear group (a) disposed on said second countershaft (b) andsaid driven shaft,

(7) and means (a) selectively operative to direct the flow of power fromsaid second gear group through said third gear group,

(b) said last named means also being selectively operative to direct theflow of power from said second gear group directly to said driven shaft.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS

